This invention pertains to electronic means and a method for determining the quantity and location of weights required for counterbalancing a rotating member.
In determining the amount of weight to be added to a rotating body in order to counterbalance the body, systems have previously been devised for detecting the peaks of waveforms and storing the value of the peaks so detected for display on meters or on light emitting character displays.
As respects the problem of determining the appropriate location for the weight, systems have previously detected a reference pulse train associated with the rotational position of the balance mechanism shaft and also detected a second pulse train. The technique was to count the number of pulses of the second pulse train between the time of cross-over of the waveform to a pulse of the first pulse train. This number than represented the rotational location of the required counterbalance weight. The number was then stored and displayed on meters or character displays.
With respect to amplitude, the present invention detects only whether or not the amplitude of the waveform exceeds a certain value. If it does, then a light flashes in response to detection of this waveform. If it does not, the light does not flash. The particular value is adjustable by the operator over a calibrated range. The adjustment is representative of the amount of counterbalance weight required.
Advantages of this approach are that no peak detection circuitry is needed and no storage is required. Additionally, an inexpensive light is used as a display instead of a meter or a light emitting character display.
With respect to the location detection portion of the system, the present invention detects only a single pulse train for a reference. The time between pulses is well established since the shaft is driven by a motor connected to the power mains. A timer is used to generate an angle pulse whose duration is varied by the operator from 1/50th to 49/50ths of the period of the shaft rotation. Further, the time of cross-over of the waveform is detected and a cross-over pulse generated at that time. If the cross-over pulse occurs at any point during the existence of the angle pulse, the circuits are arranged whereby a light will be activated. Otherwise, the light does not turn on. The location of the required counter-balance weight is determined by the operator varying the angle pulse duration until a light is just on the verge of flashing.
Advantages of the foregoing arrangement relative to detection of the angular locus of the weights to be secured to a wheel/tire combination are to be found in the fact that only one pulse train is required and no storage is necessary. Further, the display constitutes an inexpensive light instead of a meter or character display.